other: 0.088
permissions: 0.088
socket: 0.084
graphic: 0.073
device: 0.073
debug: 0.071
semantic: 0.071
vnc: 0.070
files: 0.070
network: 0.069
PID: 0.065
performance: 0.062
KVM: 0.061
boot: 0.054
debug: 0.236
files: 0.190
other: 0.107
PID: 0.076
semantic: 0.076
device: 0.056
performance: 0.045
boot: 0.041
permissions: 0.036
graphic: 0.035
network: 0.034
socket: 0.028
KVM: 0.021
vnc: 0.019

Qemu 2.3.0 failes to compile with GCC 5.1.0 and -flto

Compiling Qemu 2.3.0 failes with the following error:

x86_64-pc-linux-gnu-g++ -I/usr/include/pixman-1   -fPIE -DPIE -m64 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common  -Wendif-labels -Wmissing-include-dirs -Wempty-body -Wnested-externs -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wold-style-declaration -Wold-style-definition -Wtype-limits -fstack-protector-strong   -I/usr/include/libpng16  -I/usr/include/libusb-1.0  -I/home/gentoo/tmp/portage/app-emulation/qemu-2.3.0/work/qemu-2.3.0/tests -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include  -march=native -O2 -pipe -ggdb -floop-interchange -floop-strip-mine -floop-block -ftree-loop-distribution -fira-loop-pressure -ftree-vectorize -ftree-loop-linear -flto=5 -fuse-linker-plugin -Wl,-z,relro -Wl,-z,now -pie -m64 -Wl,-O1 -Wl,--as-needed -march=native -O2 -pipe -ggdb -floop-interchange -floop-strip-mine -floop-block -ftree-loop-distribution -fira-loop-pressure -ftree-vectorize -ftree-loop-linear -flto=5 -fuse-linker-plugin -Wl,-znow -Wl,--sort-common -Wl,--hash-style=gnu -Wl,--enable-new-dtags -o qemu-img qemu-img.o async.o thread-pool.o nbd.o block.o blockjob.o main-loop.o iohandler.o qemu-timer.o aio-posix.o qemu-io-cmds.o qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o qemu-coroutine-sleep.o coroutine-ucontext.o block/raw_bsd.o block/qcow.o block/vdi.o block/vmdk.o block/cloop.o block/dmg.o block/bochs.o block/vpc.o block/vvfat.o block/qcow2.o block/qcow2-refcount.o block/qcow2-cluster.o block/qcow2-snapshot.o block/qcow2-cache.o block/qed.o block/qed-gencb.o block/qed-l2-cache.o block/qed-table.o block/qed-cluster.o block/qed-check.o block/vhdx.o block/vhdx-endian.o block/vhdx-log.o block/parallels.o block/blkdebug.o block/blkverify.o block/block-backend.o block/snapshot.o block/qapi.o block/raw-posix.o block/linux-aio.o block/null.o block/mirror.o block/nbd.o block/nbd-client.o block/sheepdog.o block/accounting.o block/write-threshold.o block/curl.o  libqemuutil.a libqemustub.a   -lz -lbz2 -laio -lcurl -lm -lgthread-2.0 -pthread -lglib-2.0   -lz -lrt -lz -lcap-ng -luuid  -lutil
lto1: error: two or more sections for .gnu.lto_fprintf.2f4a95b725db6827
(null):0: confused by earlier errors, bailing out
make[1]: *** [/home/gentoo/tmp/portage/app-emulation/qemu-2.3.0/temp/ccEUT6Vq.ltrans11.ltrans.o] Error 1
make[1]: *** Waiting for unfinished jobs....
lto-wrapper: fatal error: make returned 2 exit status
compilation terminated.
/usr/lib/gcc/x86_64-pc-linux-gnu/5.1.0/../../../../x86_64-pc-linux-gnu/bin/ld: fatal error: lto-wrapper failed
collect2: error: ld returned 1 exit status
/home/gentoo/tmp/portage/app-emulation/qemu-2.3.0/work/qemu-2.3.0/rules.mak:122: recipe for target 'qemu-img' failed
make: *** [qemu-img] Error 1

I've found an old GCC bugreport with the same error: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52159 (which has been marked as dup of https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59000) . I was able to reduce the object list to to three .o files which reproduce the error reliably: qemu-img.o qemu-io-cmds.o block/qapi.o.

Please let me know if you need further information.

This seems to be a GCC bug, not a QEMU bug? I'm going to close this bug, since it has been reported upstream with the GCC folks, and they don't seem to think this is an error on our side.